In the power steering unit of automobiles, a steering rack and pinion are used with a rack housing. Inside the rack housing there is a shaft commonly referred to as the “bar”. Located on the bar is metal bushings that separate the two pools of hydraulic steering liquid located in the rack housing. This bushing is often referred to as the “piston”. The bar has end seals, that are replaced when the rack is reconditioned. Normally the seals can be simply removed and replaced, however where the bar has a larger end diameter, the piston must be removed to gain access to all the seals.
A number of methods are employed to secure the piston to the shaft. One method is crimping, while the other method employs a wire that is inserted in the bar and wrapped around the piston. These two methods of securing the piston to the shaft have a number of disadvantages, including difficulty in respect of removing the piston, while frequently allowing movement of the piston on shaft during operation.